Modified glenoid components and methods of installing same

ABSTRACT

A glenoid component for securement to a glenoid surface of a scapula comprises a body portion having a first surface adapted to contact the glenoid surface of a scapula and a second surface configured to receive the head portion of a humerus. The glenoid component further includes an anchor peg for penetrating the glenoid surface of the scapula so as to secure the body portion to the glenoid surface of the scapula. The anchor peg includes a cylindrical shaft extending from the first surface of the body portion and a fin secured to and extending outwardly from the cylindrical shaft. The glenoid component further includes a feature that prevents rotation of the glenoid component.

CROSS-REFERENCE TO RELATED U.S. PATENT APPLICATION

This application claims priority under 35 U.S.C. § 120 to U.S. patentapplication Ser. No. 14/853,618, entitled “MODIFIED GLENOID COMPONENTSAND METHODS OF INSTALLING SAME,” which was filed on Sep. 14, 2015, nowissued as U.S. Pat. No. 10,702,390, which claims priority under 35U.S.C. § 120 to U.S. patent application Ser. No. 13/790,633, entitled“MODIFIED GLENOID COMPONENTS AND METHODS OF INSTALLING SAME,” which wasfiled on Mar. 8, 2013, which claims priority under 35 U.S.C. § 119 toU.S. Patent Application No. 61/665,633, entitled “MODIFIED GLENOIDCOMPONENTS AND METHODS OF INSTALLING SAME,” which was filed on Jun. 28,2012. The disclosure of each above-noted application is incorporatedherein by reference.

TECHNICAL FIELD

The present disclosure relates generally to a glenoid component, andmore particularly, to a glenoid component that resists rotation andpullout and a method of implanting the glenoid component.

BACKGROUND

During the lifetime of a patient, it may be necessary to perform a totalshoulder replacement procedure on the patient as a result of, forexample, disease or trauma. In a total shoulder replacement procedure, ahumeral component having a head is utilized to replace the natural headof the arm bone or humerus. The humeral component typically has anelongated intramedullary stem that is utilized to secure the humeralcomponent to the patient's humerus. In such a total shoulder replacementprocedure, the natural glenoid surface of the scapula is resurfaced orotherwise replaced with a glenoid component which provides a bearingsurface for the head of the humeral component.

Glenoid components generally include a body that defines a bearingsurface for receiving the head of the humeral component and a number ofattachment pegs integrally formed with the body. The attachment pegs areinserted and thereafter secured into a corresponding number of holesthat are drilled in the glenoid surface of the scapula by use of bonecement. The pegs prevent rotation of the glenoid component.

SUMMARY

According to an illustrative embodiment, a glenoid component forsecurement to a glenoid surface of a scapula so as to provide a bearingsurface for a head portion of a humerus comprises a body portion and ananchor peg. The body portion includes a first surface adapted to contactthe glenoid surface of a scapula and a second surface configured toreceive the head portion of the humerus. The anchor peg is forpenetrating the glenoid surface of the scapula so as to secure the bodyportion to the glenoid surface of the scapula. The anchor peg includes acylindrical shaft extending from the first surface of the body portionand a fin secured to and extending outwardly from the cylindrical shaft,the fin being generally square-shaped.

The glenoid component includes a plurality of generally square-shapedfins secured to and extending outwardly from the cylindrical shaft ofthe anchor peg.

The fins are generally square-shaped and have rounded corners.

The anchor peg is adapted for insertion into a hole within a glenoidsurface of a scapula and the fins have a width that is greater than awidth or diameter of a hole in which the anchor peg is inserted. Thefins are configured to prevent rotation of the glenoid component withinthe glenoid surface.

Side edges of the fins are configured to have an interference with awall forming a hole in which the anchor peg is inserted of between about0.25 millimeters and about 2 millimeters.

Rounded corners of the fins are configured to have an interference withthe wall forming the hole in which the anchor peg is inserted of betweenabout 0.5 millimeters and about 3 millimeters. The interference betweenthe side walls and the rounded corners with the wall forming the holeprevent rotation of the glenoid component.

The anchor peg is configured for insertion into a generallysquare-shaped hole in the glenoid surface of the scapula.

According to a further illustrative embodiment, a glenoid component forsecurement to a glenoid surface of a scapula so as to provide a bearingsurface for a head portion of a humerus comprises a body portion, ananchor peg, and at least one gusset. The body portion includes a firstsurface adapted to contact the glenoid surface of a scapula and a secondsurface configured to receive the head portion of the humerus. Theanchor peg is for penetrating the glenoid surface of the scapula so asto secure the body portion to the glenoid surface of the scapula. Theanchor peg includes a cylindrical shaft extending from the first surfaceof the body portion and a fin secured to and extending outwardly fromthe cylindrical shaft. The at least one gusset is secured to andextending downwardly from the first surface of the body portion andsecured to and extending outwardly from the cylindrical shaft of theanchor peg.

An angled edge is formed by the gusset and extends between the firstsurface of the body portion and the anchor peg.

The angled edge of the gusset is configured to be driven into theglenoid surface of the scapula to prevent rotation of the glenoidcomponent.

The glenoid component includes a plurality of gussets secured to andextending downwardly from the first surface of the body portion andsecured to and extending outwardly from the cylindrical shaft of theanchor peg.

The gussets are orthogonal to the first surface of the body portion andthe cylindrical shaft of the anchor peg.

Four gussets are spaced about a longitudinal axis of the anchor peg withabout ninety degrees between adjacent gussets.

The gussets are configured to be driven into the glenoid surface of thescapula to prevent rotation of the glenoid component.

According to another illustrative embodiment, a glenoid component forsecurement to a glenoid surface of a scapula so as to provide a bearingsurface for a head portion of a humerus comprises a body portion and ananchor peg. The body portion includes a first surface adapted to contactthe glenoid surface of a scapula and a second surface configured toreceive the head portion of the humerus. The anchor peg is forpenetrating the glenoid surface of the scapula so as to secure the bodyportion to the glenoid surface of the scapula. The anchor peg includes acylindrical shaft extending from the first surface of the body portionand a fin secured to and extending outwardly from the cylindrical shaft.The fin includes at least one cutout configured to allow the fin todeflect outwardly along a hole in which the glenoid component issecured, thereby preventing rotation of the glenoid component.

The fin includes first and second opposing cutouts, wherein each of thecutouts includes a first leg and a second leg forming generallytriangular cutouts.

The cutouts are symmetrical about an axis that bisects the fins.

The body portion of the glenoid component is generally circular.

Other aspects and advantages of the present disclosure will becomeapparent upon consideration of the following drawings and detaileddescription, wherein similar structures have similar reference numbers.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the following figures,in which:

FIG. 1 is a top perspective view of a first embodiment of a glenoidcomponent;

FIG. 2 is a bottom perspective view of the glenoid component of FIG. 1 ;

FIG. 3 is a side elevational view of a second embodiment of a glenoidcomponent;

FIG. 4 is a bottom perspective view of the glenoid component of FIG. 3 ;

FIG. 5 is a bottom perspective view of a third embodiment of a glenoidcomponent;

FIG. 6 is a bottom perspective view of a fourth embodiment of a glenoidcomponent;

FIG. 7 is a bottom elevational view of the glenoid component of FIG. 6and showing a shape of fins that extend outwardly from an anchor peg ofthe glenoid component;

FIG. 8 is a perspective view depicting a glenoid surface of a scapulawith a hole for securing a glenoid component to the glenoid surface;

FIG. 9 is a partial exploded perspective view depicting the glenoidcomponent of FIG. 1 secured within the glenoid surface of FIG. 8 andfurther showing a humeral component;

FIG. 10 is a cross-sectional view taken generally along the lines 10-10of FIG. 9 and depicting deflection of fins of the glenoid component ofFIGS. 1 and 2 after securing the glenoid component within the glenoidsurface;

FIG. 11 is a cross-sectional view taken generally along the lines 11-11of FIG. 9 and depicting a sample level of interference between the finsof the glenoid component of FIGS. 1 and 2 and walls forming the holeformed within the glenoid surface;

FIG. 12 is a cross-section view similar to that of FIG. 10 and depictingthe glenoid component of FIG. 3 secured within the glenoid surface;

FIG. 13 is a perspective view of a tool that may be used to prepare theglenoid surface prior to securing the glenoid component of FIG. 3thereto;

FIG. 14 is a diagrammatic view of an orthopaedic surgical tool having acutting bit configured to make a square-shaped hole; and

FIG. 15 is a perspective view of the cutting bit of the orthopaedicsurgical tool of FIG. 14 .

DETAILED DESCRIPTION OF THE DRAWINGS

While the concepts of the present disclosure are susceptible to variousmodifications and alternative forms, specific exemplary embodimentsthereof have been shown by way of example in the drawings and willherein be described in detail. It should be understood, however, thatthere is no intent to limit the concepts of the present disclosure tothe particular forms disclosed, but on the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the appended claims.

Terms representing anatomical references, such as anterior, posterior,medial, lateral, superior, inferior, etcetera, may be used throughoutthis disclosure in reference to both the orthopaedic implants describedherein and a patient's natural anatomy. Such terms have well-understoodmeanings in both the study of anatomy and the field of orthopaedics. Useof such anatomical reference terms in the specification and claims isintended to be consistent with their well-understood meanings unlessnoted otherwise.

Referring now to the figures, a first embodiment of a polymer glenoidcomponent 20 is depicted in FIGS. 1 and 2 . The glenoid component 20includes a body 22 having a generally convex surface 24 and a generallyconcave surface 26 opposite the convex surface 24. The convex surface 24generally abuts or otherwise contacts at least a portion of the glenoidsurface of the scapula. The body 22 of the glenoid component 20generally has a shaped that is generally circular, such that the concavesurface 26 generally forms a spherical surface. In this manner, theconcave surface 26 of the body 22 provides a smooth bearing surface uponwhich the head 28 articulates and which generally matches the shape ofthe spherical head 28.

The glenoid component 20 also includes an anchor peg 40 secured to andextending generally orthogonal to the convex surface 24 of the body 22.As shown in FIGS. 1 and 2 , the anchor peg 40 includes a cylindricalshaft 42 and a tapered head 46 at an end of the cylindrical shaft 42that functions as a lead-in to facilitate insertion into a hole 48drilled or otherwise formed in a glenoid surface 50 (as shown in FIGS. 8and 9 ) of a patient's scapula 52. The anchor peg 40 may include a firstcylindrical shaft segment extending from the convex surface 24 andhaving a first diameter and a second cylindrical shaft segment extendingfrom the first cylindrical shaft segment and having a second diameterless than the first diameter, as seen in FIGS. 1 and 2 . Alternatively,the anchor peg 40 may have a single diameter throughout a length of thecylindrical shaft 42.

The anchor peg 40 further includes a plurality of flexible radial fins60 extending outwardly from an end 62 of the anchor peg 40. The fins 60function to secure the glenoid component 20 within the glenoid surface50. In addition, the flexible and deformable nature of the radial fins60 extending from the anchor peg 40 allow the fins 60 to deform uponinsertion of the anchor peg 40 into the hole 48, thereby creatingresistance to extraction of the anchor peg 40 from the hole 48 oncefully inserted therein.

The fins 60 of glenoid component 20, as best seen in FIGS. 1 and 2 , aregenerally square-shaped with rounded corners 62. The fins 60 have a sizeand shape that creates an interference with walls forming the hole 48that prevents easy removal of the glenoid component 20 from the glenoidsurface 50 and prevents rotation of the glenoid component 20 without theuse of a stabilizing peg, as will be discussed in greater detailhereinafter.

A second embodiment of a glenoid component 80 is depicted in FIGS. 3 and4 . The glenoid component 80 is similar to the glenoid component 20 ofFIGS. 1 and 2 in that it includes a body 82 with opposing generallyconvex and generally concave surfaces 84, 86. The glenoid component 20also includes an anchor peg 90 with a cylindrical shaft 91 and a taperedend 92. One manner in which the glenoid component 80 is different fromthe glenoid component 20 of the first embodiment is that it includes aplurality of generally circular fins 96 extending outwardly from an end98 of the anchor peg 90.

Referring again to FIGS. 3 and 4 , the glenoid component 80 furtherincludes a plurality of gussets 100 extending downwardly from the convexsurface 84 and outwardly from the anchor peg 90 adjacent the convexsurface 84 of the body 82. The gussets 100 are also generally orthogonalto the convex surface 84 and the anchor peg 90 and extend outwardly fromthe peg 90 a distance greater than the fins 96 extend from the peg 90.An outer angled edge 102 of each gusset 100 extends between and isintegrally attached to the convex surface 84 and the anchor peg 90. Thegussets are spaced about a longitudinal axis 104 of the anchor peg 90with about ninety degrees between adjacent gussets 100.

When the glenoid component 80 is installed within the glenoid surface50, the gussets 100 are pressed into the glenoid surface 50 surroundingthe anchor peg 90 and below the convex surface 84 of the body 82,thereby preventing rotation of the glenoid component 80 without the useof a stabilizing peg. Installation and functionality of the glenoidcomponent will be discuss in greater detail below with respect to FIG.13 .

While four gussets 100 are depicted with respect to the embodiment ofthe glenoid component 80 of FIGS. 3 and 4 , one or more gussets 100 maybe utilized. In one embodiment, a single gusset 100 may be utilized. Inanother embodiment, eight gussets 100 may be utilized. The number ofgussets 100 utilized may be determined based on the ability of thosegussets 100 to prevent rotation of the glenoid component 80, the cost ofadditional gussets 100, and/or other factors.

A third embodiment of a glenoid component 120 is shown in FIG. 5 . Theglenoid component 120 is similar to the glenoid component 80 of FIGS. 3and 4 and, thus, similar features will be numbered similarly. The maindifference is that the glenoid component 120 does not include gussets,but rather, includes a stabilizing peg 122 extending outwardly from theconvex surface 84. The stabilizing peg 122 is spaced between the anchorpeg 90 and an outer edge 124 of the body 82. While one stabilizing peg122 is shown, other stabilizing pegs 122 may be spaced about the convexsurface 84.

The stabilizing peg 122 prevents the body 82 of the glenoid component120 from moving a plane perpendicular to the anchor peg 90 and preventrotational movement of the glenoid component 120. Generally, thestabilizing peg 122 is shorter than the anchor peg 90. Moreover, ifmultiple stabilizing pegs 122 are utilized, one or more of thestabilizing pegs 122 may be shorter than the others, although otherconfigurations may be used.

While the body 82, the anchor peg 90, and the stabilizing peg 122 of theglenoid component 120 are shown as being integral, one or more of theanchor peg 90 or stabilizing peg 122 may be separately secured to thebody 82. As one skilled in the art would understand, any number ofanchor pegs 90 or stabilizing pegs 122 may be utilized, the anchor peg90 may include any features that aid in inserting the anchor peg 90 intoa hole or retaining the anchor peg 90 within a hole, and/or theplacement of the anchor peg(s) 90 and/or stabilizing peg(s) 122 may bemodified without departing from the scope of the present disclosure.

In the embodiment of FIG. 5 , one or more secondary holes (not shown)would be formed within the glenoid surface 50 and spaced between thehole 48 and an outer edge of the glenoid surface 50. The secondary holesmay have a size and shape that conforms to the stabilizing peg(s) 122.

A fourth embodiment of a glenoid component 150 is depicted in FIG. 6 .The glenoid component 150 is similar to the glenoid component 80 ofFIGS. 3 and 4 . In particular, the glenoid component 150 includes asimilar body 82 with convex and concave surfaces 84, 86 and an anchorpeg 90 having a cylindrical shaft 91 and a tapered end 92 and extendingoutwardly and transversely to the convex surface 84. The glenoidcomponent 150 further includes a plurality of fins 152 extendingoutwardly from an end of the anchor peg 90. Upon insert of the anchorpeg 90 into the hole 48, portions of the fins 152 deflect outwardly(toward an opening of the hole 48), thereby preventing rotation of theglenoid component 150 without the use of a stabilizing peg.

Each of the fins 152 is generally disc-shaped and includes two opposingcutouts 154. The cutouts 154 are generally triangular in shape and aregenerally symmetrical about an axis 155 that bisects the fins 152.Optionally, the cutouts 154 may be asymmetrical. Each cutout 154includes first and second legs 156, 158 that extend at an angle A withrespect to one another. The first leg 156 of each cutout 154 extends atan angle B with respect to a line 160 tangent to an outer end of thefirst leg 156 and the second leg 158 of each cutout 154 extends at anangle C with respect to a line 162 tangent to an outer end of the secondleg 158. Optionally, the cutouts 154 may be formed of another shape, forexample, square-shaped or U-shaped. The cutouts 154 allow bone to growbetween the fins 152 in two planes. While two cutouts 154 are depicted,any number of cutouts 154 is possible.

The glenoid components shown and described herein may be made of apolymeric material, for example, a polyethylene. One example of asuitable polyethylene is ultrahigh molecular weight polyethylene(UHMWPE). In addition to polymers, the glenoid components may be madefrom ceramic, metal, or a composite material. Examples of thesematerials include alumina, zirconia, and alumina/zirconia composite orcomposite material.

A method of securing the glenoid component 20 of FIGS. 1 and 2 to theglenoid surface 50 of the scapula 52 will now be discussed in detailwith reference to FIGS. 8-11 . A drill is used to bore the hole 48through the glenoid surface 50 and into the scapula 52 in a manner knownin the art and, thereafter, the anchor peg 40 of the glenoid component20 is press fit or otherwise interference fit into the hole 48. Duringinstallation, the rounded corners 62 and/or side edges 170 between therounded corners 62 of the square-shaped fins 96 deflect outwardly (ortoward an opening of the hole 48), thereby creating an interference witha wall forming the hole that prevents rotational movement of the glenoidcomponent 150 and prevents the glenoid component 20 from moving in aplane perpendicular to the anchor peg 40. While the hole 48 is depictedherein as having a circular cross-section, the hole may optionally havedifferent cross-sections for any of the embodiments disclosed herein,for example, a square-shaped cross section.

As can be seen in FIG. 11 , which depicts a range of interferencebetween the fins 60 and a wall forming the hole 48, the square shape ofthe fins 60 provides a greater interference at the corners 62 of thefins 60 than at the side edges 170 of the fins 96. In one embodiment, aninterference between the side edges 170 of the fins 60 and the wall ofthe hole 48 is between about 0.25 millimeters (mm) and about 2 mm and aninterference between the corners 62 of the fins 60 and the wall of thehole 48 is between about 0.5 mm and about 3 mm. In another embodiment, awidth of the square fins 60 is greater than a diameter of the hole 48.

The deflection of the fins 60 upon insertion of the glenoid component 20into the hole 48 is depicted in FIG. 10 . In particular, the corners 62of the fins 60 are deflected outwardly a greater distance than the sideedges 170 of the fins 60 are deflected due to the difference in overallinterference.

If the hole in which the glenoid component 20 is installed has asquare-shaped cross-section, a hole 172 may be be created utilizing atool having a bit 174 with a general profile of a Reuleux triangle 176,as seen in FIGS. 14 and 15 . In particular, a Reuleux triangle 176 iscreated by starting with an equilateral triangle 178 with sides oflength S. With a radius equal to S and a center at a vertice of thetriangle 178, three arcs 180 are drawn to form the Reuleux triangle 176.The bit 174, as noted above, has an outer profile that forms the Reuleuxtriangle 176, such that, when the bit is rotated about a circle 182starting at a center 184 of the equilateral triangle 178, asquare-shaped hole 172 with rounded corners is formed. The glenoidcomponent 20 is secured in the same manner when the hole 172 with asquare-shaped cross-section is used. A length of a side of the squareforming the fins 96 may be greater than a length of a side of the squareforming the hole 172, thereby forming an interference fit. Uponinsertion of the gleonid component 20, the rounded corners 62 and theside edges 170 of the fins 96 deflect outwardly (toward an opening ofthe hole 172). The square shapes would prevent rotation of the glenoidcomponent 20.

Methods of securing the glenoid component 80 of FIGS. 3 and 4 to theglenoid surface 50 of the scapula 52 will now be discussed in detailwith reference to FIGS. 12 and 13 . A hole 48 is bored into the glenoidsurface 50 of the scapula 52 in any manner known in the art. Thereafter,a tool 200 as shown in FIG. 13 , may be used to create slots within theglenoid surface 50 surrounding the hole 48. The tool 200 generallyincludes a handle 202, a rod 204 extending from an end 206 of the handle202, and a punch 208 attached to an end 210 of the rod 204. The punch208 includes a plate, for example, a disc 212 having a cylinder 214extending from a surface 216 of the disc 212 opposite the rod 204. Thecylinder 214 is shaped and sized to have a diameter that interferes withthe hole 48. In particular, the cylinder 214 has a diameter that islarger than a diameter than the hole 48 and smaller than a diameter ofthe fins of a glenoid component that fits within the hole 48. Triangulargussets 218 extend outwardly from the cylinder 214. The gussets 218 aresimilar in size, shape, and number to the gussets 100 of the glenoidcomponent 80. In particular, the gussets 218 are generally orthogonal tothe disc 212 and extend outwardly and are generally orthogonal to thecylinder 214. Each gusset 218 is also disposed about 90 degrees aroundthe cylinder 214 from an adjacent gusset 218. Should more or lessgussets 100 be formed within a glenoid component, the tool 200 may bemodified accordingly.

The tool 200 is grasped by the handle 202, the cylinder 214 of the tool200 is inserted into the hole 48, and pressure is exerted on the tool200 toward the glenoid surface 50, thereby creating slots in the glenoidsurface 50 corresponding to the gussets 218. The anchor peg 90 of theglenoid component 80 may thereafter be inserted into the hole 48, in themanner described with respect to the first embodiment, until the gussets218 are disposed within the slots created by the tool 200.

The glenoid component 80 may be secured to the glenoid surface 50without the use of the tool 200. In such an embodiment, the anchor peg90 of the glenoid component 80 would be inserted into the hole 48 andthe gussets 100 would be driven into the glenoid surface 50, therebycreating the slots in which the gussets 100 are disposed.

The glenoid component 120 of FIG. 5 is secured to the glenoid surface 50in a manner similar to that of the glenoid component 20 except that asecondary hole is created and, during installation of the glenoidcomponent 120, the stabilizing peg 122 is aligned with and inserted intothe secondary hole.

The anchor peg 90 of the glenoid component 150 of FIG. 6 is also securedto the glenoid surface 50 in a manner similar to that of the glenoidcomponent 20. During installation, the cutouts 154 in the fins 152 ofthe glenoid component 150 allow the fins 152 to deflect outwardly (ortoward an opening of the hole 48), thereby creating an interference witha wall forming the hole that prevents rotational movement of the glenoidcomponent 150 and movement of the glenoid component 150 in a planeperpendicular to the glenoid component 150.

The configurations of the fins and/or gussets as shown and describedherein eliminate the need for the use of bone cement to secure theanchor peg to the glenoid surface 50 of the scapula 52, thereby reducingthe complexity of a typical shoulder replacement procedure.

While the glenoid components shown in the figures and described indetail include have a generally circular configuration, as describedabove, the principles of the present disclosure may be implementedwithin a glenoid component having any configuration, for example,oval-shaped. One advantage provided by the glenoid components having acircular configuration is that the glenoid component does not have to bealigned in a specific position or orientation.

As will become apparent from reading the present specification, any ofthe features of any of the embodiments disclosed herein may beincorporated within any of the other embodiments without departing fromthe scope of the present disclosure.

While the disclosure has been illustrated and described in detail in thedrawings and foregoing description, such an illustration and descriptionis to be considered as exemplary and not restrictive in character, itbeing understood that only illustrative embodiments have been shown anddescribed and that all changes and modifications that come within thespirit of the disclosure are desired to be protected.

There are a plurality of advantages of the present disclosure arisingfrom the various features of the apparatus, system, and method describedherein. It will be noted that alternative embodiments of the apparatus,system, and method of the present disclosure may not include all of thefeatures described yet still benefit from at least some of theadvantages of such features. Those of ordinary skill in the art mayreadily devise their own implementations of the apparatus, system, andmethod that incorporate one or more of the features of the presentinvention and fall within the spirit and scope of the presentdisclosure.

The invention claimed is:
 1. A glenoid component for securement to aglenoid surface of a scapula so as to provide a bearing surface for ahead portion of a humerus, the glenoid component comprising: a bodyportion having (i) a first surface adapted to contact the glenoidsurface of a scapula and (ii) a second surface configured to receive thehead portion of the humerus; and an anchor peg for penetrating theglenoid surface of the scapula so as to secure the body portion to theglenoid surface of the scapula, wherein the anchor peg includes (i) acylindrical shaft extending from the first surface of the body portionand (ii) a fin secured to and extending outwardly from the cylindricalshaft, the fin being generally square-shaped.
 2. The glenoid componentof claim 1, further including a plurality of generally square-shapedfins secured to and extending outwardly from the cylindrical shaft ofthe anchor peg.
 3. The glenoid component of claim 2, wherein thegenerally square-shaped fins have rounded corners.
 4. The glenoidcomponent of claim 3, wherein the anchor peg is adapted for insertioninto a hole within a glenoid surface of a scapula and wherein the finshave a width that is greater than a width or diameter of a hole in whichthe anchor peg is inserted and further wherein the fins are configuredto prevent rotation of the glenoid component within the glenoid surface.5. The glenoid component of claim 2, wherein side edges of the fins areconfigured to have an interference with a wall forming a hole in whichthe anchor peg is inserted of between about 0.25 millimeters and about 2millimeters.
 6. The glenoid component of claim 5, wherein roundedcorners of the fins are configured to have an interference with the wallforming the hole in which the anchor peg is inserted of between about0.5 millimeters and about 3 millimeters, and wherein the interferencebetween the side walls and the rounded corners with the wall forming thehole prevent rotation of the glenoid component.
 7. The glenoid componentof claim 2, wherein the anchor peg is configured for insertion into agenerally square-shaped hole in the glenoid surface of the scapula.